<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02_JS的变量与常量</title>
</head>
<body>
    <script>
      var a = 10;
      console.log(a,typeof a);
      var b = "aa";
      console.log(b,typeof b);
      var c = 3.14;
      console.log(c,typeof c);
      var d = true;
      console.log(d,typeof d);
      d = 'j';
      console.log(d,typeof d);
      var d = "hhhhhhh";
      console.log(d,typeof d);

      let x = 1;
      x = 3.14;
      // let x = 2;
      console.log(x);

      const y = 1;
      console.log(y);
      // y = y+1;

    </script>
</body>
</html>